Electric discharge device



April 19, 1960 H. c. SPICER EI'AL 2,933,633

ELECTRIC DISCHARGE DEVICE Filed Feb. 16, 1955 2 Sheets-Sheet 1 FIG!FIG.2 v

lNVENTORS RICHARD F. HAMMOND,

HUGH c. SPICER,

April 19, 1960 H. c. SPICER E 2,933,633

\ ELECTRIC DISCHARGE osvxcs Filed Feb. 16, 1955 2 Sheets-Sheet 2 FIG.3

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lNVENTORS RICHARD F. HAMMOND,

HUGH c. SPICER,

B YWQZZM.

'I'HEIR TOR Y.

United States, Patent Ofiice ELECTRIC DISCHARGE DEVICE Hugh C. Spicerand Richard F. Hammond, Tell City,

Ind., assignors to General Electric Company, a corporation of New YorkApplication February 16, 1955, Serial No. 488,462

3 Claims. (Cl. 313-313) Our invention relates to electric dischargedevices and pertains more particularly to a new and improved highvoltage electric discharge device.

During the operation of some high voltage electric discharge devicesincluding glass bulbs, such as high voltage regulator and rectifiertubes used in television receivers, the interior surfaces of the bulbsare bombarded with electrons and are alternately charged and discharged.This sometimes results in the generation of a signal with harmonicsextending into the television spectrum and causing radio frequencynoise'generally known in the art as diodehausen. The diodehausenmanifests itself in some television receivers as undesirable blackvertical lines at some particular portions of the raster. Additionally,the charging of the bulbs results in glass electrolysis which is alsoundesirable.

The primary object of our invention is to provide a new and improvedhigh voltage electric discharge device including means for minimizingthe effects of bulb chargmg.

Another object of our invention is to provide a new and improved highvoltage tube adapted for use in television receivers and including meansfor minimizing radio frequency noise in the receivers.

Another object of our invention is to provide a new and improved highvoltage electric discharge device including a vitreous envelope andmeans for minimizing electrolysis in the walls thereof.

Further objects and advantages of our invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize our invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In carrying out the objects of our invention we provide an electricdischarge device including a vitreous envelope provided with a metallicdeposition on the interior surface thereof. The metallic deposition ispreferably lead andmay be applied by providing in the envelope amaterial which will vaporize and flash onto a portion of the walls ofthe envelope with lead when heated to a predetermined degree.Vaporization of the material and flashing of the lead may be effected bydepositing the material on an electrode in the device and electricallyheating the electrode. The methods of producing the electric dischargedevice and electrodes are described and claimed in our co-pendingdivisional application Serial Number 817,429 filed May 12, 1959, andassigned to the same assignee as the present invention.

For a better understanding of our invention reference may be had to theaccompanying drawing in which:

Fig. 1 is an elevational view of an electric discharge deviceincorporating our invention and partially broken away to illustrate themanner in which the metallic deposition is provided on the interiorsurface of the bulb;

Pig. 2 is a somewhat schematic illustration of one manner in which ourinvention may be practiced;

Fig. 3 is a fiow chart illustrating one manner of preparing electrodesfor use in our invention; and

for preparing the electrodes.

Referring to Fig. 1, there is shown an electric dischargedevice in theform of a high voltage rectifier tube generally designated 1. The tube 1includes a glass bulb or envelope 2 in which is housed a cylindricalanode 3 mounted in a suspended manner in the envelope by means of a topcap 4 which extends through and is suitably sealed in the top portion ofthe envelope.

The anode and top cap are often collectively referred to as an anodeassembly. Mounted in the envelope by means of a pair of vertical supportrods 5 and disposed in the anode 3 is a filament or cathode 6. Suitablysup ported beneath the anode 3 and in spaced relation thereto is ashield 7. Suitably secured to the lower end of the envelope 2 is a base8 carrying a plurality of base pins and a bayonet plug 10 adapted forfacilitating insertion of the pins in a tube socket. Leads 11 areelectrically connected to the various pins 9 and extend in a sealedmanner through the lower end of the envelope for making electricalconnections to and supporting the filament support rods 5 and the shield7 in the envelope. Also, as indicated above, the described methods ofproducing electric discharge devices and electrodes are claimed in ourcopending divisional application Serial Number 817,429.

During normal operation of a high voltage rectifier tube such as thatdescribed to this point and not incorporating our invention, theinterior surface of the bulb 2 is bombarded by electrons and tendsalternately to charge and discharge. This charging and discharging isfrequent and abrupt and often results in radiation of energy andgeneration of a signal with harmonics extending into the televisionspectrum. As a'result, if the tube is used in a television receiver, itcauses radio frequency noise generally referred to in the art asdiodehausen. Diodehausen sometimes manifests itself in a televisionreceiver as a black vertical line appearing at some particular portionof the raster, such as the left hand edge. Additionally, the referred-toelectron bombardment of the glass causes undesirable glass electrolysis.

The bulb charging described above is ordinarily most.

prevalent or concentrative in the annular area extending between thebottom of the anode 3 and the top of the shield 7 and defined by thespaced dash lines 12 in Fig. 2. In order to minimize the bulb chargingand thereby avoid diodehausen in television receivers utilizing tubessuch as 1 and to minimize glass electrolysis, we vaporize a material inthe tube in the vicinity of the area defined by the lines 12, whereby athin lead deposition indicated by stippling designated 15 in Fig. 1 isprovided on the interior surface of the bulb. The deposition 15 extendsover and beyond the area ordinarily bombarded by electrons during tubeoperation but is not so extensive as to effect a conductive path betweenthe top cap 4 and the leads 11.

The lead deposition 15 is effective for distributing the charge orconducting the electrons bombarding the walls of the bulb in 'this areain such a manner that large charges are prevented from building up oraccumulating in any particular spots or areas. This reduces theabovereferred'to energy radiation or signal generation to the extentthat when a tube such as that described is employed in a televisionreceiver diodehausen is not en-" countered. Additionally, due to thereduction of the concentrated charging by the metallic deposition 15glass electrolysis is minimized. As a result, in some tube struc-' turesWhere lead glass was formerly used because .of its relatively highresistance to current flow, with our inven-J tion a relatively lessexpensive glass such as lime glass may be employed. In some other tubestructures where it is desired to use much higher voltages and whereelec trolysis effects would be encountered even where lead Patented Apr.'19, 1960;

, anode through the oven. 7

V 3 l glass is employed'our invention may be advantageously utilized inconjunction with the lead glass.

The lead deposition 15 is preferably applied by substantiallyuniformlydistributing in the rim or rolled lip 16 of the anode 3adeposit 17 of material which when sufilciently heated will volatilizeand flash lead on the interior of the bulb. 7

As seen in Fig. 2, the heating may be done inductively by an inductioncoil 13. Additionally, the flashing of the material 17 may be carriedout before the tube 1 is tipped-oil and while it is being processed onthe usual tube processing equipment.

Specifically, the lead may be flashed on the bulb while the tube 1 isheld by its exhaust tubulation 19 in an exhaust head 2% of the mentionedusual processing e uipment and while the anode 3 is being inductivelyheated by means of the coil 13 for elfecting out-gassing thereof.

The flashing of the lead onto the bulb occurs at approximately 390 to900 C. Thus, it will be seen that by uniformly distributing the material17 in the anode rim l6 and by taking advantage of the step of heatingthe anode for outgassing we accomplish the provision of a leaddeposition or coating 15 on the interior surface of the bulb which issubstantially uniformly distributed around the tube and covers andextends beyond the area in which bulb charging is most prevalent in anordinary rectifier tube.

The material 17 which is adapted for vaporizing and flashing the loaddeposition 15 on the wall of the bulb is preferably lead or any suitablecompound of lead, such as basic lead carbonate, which will break down touncombined lead when heated sufficiently under. exhaust conditions orwhen heated sufficiently in a vacuum.

In Fig. 3 is illustrated a method of providing a substantially uniformdeposit of basic-lead carbonate in the rim 16 of an anode 3. In thismethod the anode is dipped with the rimmed edge downward into areceptacleZl' containing'a suspension of basic lead carbonate designated22.

. Following clipping of the anode 3 in the suspension 22 in the mannerillustrated in Fig. 3, the anode 3 is set to drain on a drainboard 23 orthe like. Thus, the rim 16 is filled with a quantity of the suspension22.. Following draining, the anode is placed in a suitable drying oven 2In the oven the anode is heated for evaporating the liquid constituentof thesuspension in the anode rim. Thus, a substantially uniformlydistributed deposit or residue of basic lead carbonate 17 is left in theanode rim. It will be seen that a plurality of anodes may be held in arack or the like and dipped, drained and dried together to increaseproduction.

' After preparation of an anode in the just-described 'manner it may bemounted or suspended in the bulb by" means. of a. suitableglass-to-metal seal between the bulb and the top cap 4-, and the bulbmay be sealed to the tube stern including the tubulation 19 thereby toarrive at the structure shown in Fig. 2. Thereafter, the tube may beprocessed in the usual manner and, as described In Fig. 4 is illustrated"an automatic method of pre paring the anodes. In this method the anodesare placed on conveying means generally designated 25- adapted a supplyof the suspension 22 and then through a suitable .oven2-7. The oven 27is similar in construction and purpose to that referred to above anddesignated 24 in Fig.

. 3, but is relatively and preferably longer in order to enable completeevaporation of the liquid constituent of the suspension in the anode rimduring transit of the By means of a tube 28 including a control valve 39and automatic means generally designated 31 adapted conveying means 25is thereafter effective for directly carrying the anode into and throughthe elongated oven 27 wherein the liquid portion of the suspension isevaporated leaving in the rim a deposit 17 of basic lead carbonate to beflashed. Thereafter the anode is automatically removed from theconveying means and at this stage it is prepared for mounting in thebulb 2 and flashj ing of the basic lead carbonate for providing the leaddeposition 15 in themanner described above with regard to Fig. 2. Y

While we have shown conveying means including what is illustrated as aconveying belt, the conveying means may take any form. For instance, achain drive or the like including clamping means or magnetic holdingmeans for holding the anode assemblies by the top caps 4 thereof andthus carrying them to and positioning them at a reservoir such as 26 andthrough an elongated oven such as 27 may be employed. V

The lead suspension utilized in both of the above-described methods'ofpreparing the anodes 3 may be a leadmethanol corrosion product. Inan'operative arrangement we have found that the product may be preparedby taking a sheet of lead of approximately twelve square feet, rollingit to form a cylinder and immersing it in ap proximately twenty-eightgallons of commercially available methanol for approximately twenty-fourhours. A suspension obtained in this manner is particularly satisfactoryin that it requires no agitation to prevent settling and assuressubstantial uniformity in the amounts of lead carbonate received in therims of successively processed anodes. It will, of course, be understoodthat the'foregoing is exemplary only and is not intended to be limitingin any manner.

' positioning each anode first at a reservoir 26 containing alsogenerally commercially available.

The suspension 22 may also be prepared from powdered basic leadcarbonate popularly known as white lead and generally commerciallyobtainable. First, a stock or paste may be prepared by mixingapproximately 450 grams of white lead and approximately 300 cubiccentimeters of generally commercially available amyl acetate.

This mixture is then milled, asby ball milling, for ap-' proximatelyninety-two hours to minimize settling during use. The stock or pasteobtained in'the first described manner is used in proportions ofapproximately one and one-half cubic centimeters to a gallon of acetonewhich is A suspension obtained in the just-described manner isparticularly adaptable for use with the automatic or machine fillingmethod shown in Fig. 4 because of its drying and low odor qualities.Additionally, for most satsifactory results and, specifically, in orderto avoid settling and thereby insure substantially uniform amounts oflead carbonate in the rims of successively filled anodes, it isadvisable to agitate the suspension obtained by using the powdered basiclead carbonate;

It will be understood that the suspension 22 may be one of uncombined ormetallic lead; Additionally, while the use of the suspension fordepositing the basic lead carbonate in the anodes 3 has been foundexpedientfrom a manufacturing standpoint, if desired the lead or leadcompound may be directly placed or deposited in the rim.

It is to be understood further that while we have shown and. describedthe material to be flashed as deposited in the anode rim, this, materialcould alternatively be held in any desired manner adjacent the region orarea to be circuit completed through appropriate ones of the pins 11,thereby to raise the temperature of the material to the flashing point.

While we have shown and described specific forms of our invention we donot desire our invention to be limited to the particular forms shown anddescribed, and we intend by the appended claims to cover allmodifications within the spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. An electric discharge device comprising; a plurality of electrodes, acylindrical vitreous envelope containing said electrodes and having saidelectrodes cooperating in the central region thereof, conductiveelements extending through and sealed in both ends of said envelope andconnected tosaid electrodes, said envelope having an internal annularsurface area subject to concentrative electrical charging during normaloperation of said device, said area being confined to the central regionof said envelope immediately adjacent said electrodes and substantiallylongitudinally spaced inwardly from both ends of said envelope and saidseals, and a continuous annular elemental lead flash on only saidinternal surface area and efiective for distributing electrical chargesthereon, said flash being substantially longitudinally spaced andelectrically insulated from all conductive elements in the walls of saidenvelope.

2. A high voltage electric discharge device comprising; a plurality ofelectrodes including a tubular anode, an elongated glass envelopecontaining said electrodes, conductive elements extending through theopposite end walls of said envelope and connected to said electrodes,said conductive elements including an element mounting said anode fromone end of said envelope and supporting said anode in said envelope inspaced relation to the side walls thereof, said envelope having anintermediate annular internal surface area immediately adjacent theinner end of said anode subject to concentrative electrical chargingduring normal operation of said device, whereby undesired energyradiation and glass electrolysis are effected, and an annularlycontinuous elemental lead flash on only said annular internal surfacearea of said envelope being effective for distributing electricalcharges thereon, thereby to minimize said undesired energy radiation andglass electrolysis, said flash terminating at points substantiallylongitudinally spaced inwardly from said opposite end walls of saidenvelope and said conductive elements sealed in said end walls, saidflash being electrically insulated from all electrodes in said envelopeand from all conductive elements in the walls of said envelope, and saidlead flash relying on the thinness thereof to afford highresistivityconduction for said electrical charges.

3. A high voltage rectifier device comprising; an elongated cylindricalglass envelope, said envelope containing a filamentary cathode and acylindrical anode surrounding said cathode, said anode being mounted insaid envelope in spaced relation to the walls thercofby a conductivemember extending through one end of said en velope, said cathode beingmounted in said envelope by leads extending through the opposite ends ofsaid envelope, a shield member in said envelope between said anode andthe opposite end of said envelope and surrounding said leads, saidenvelope having an annular internal surface area which is substantiallycoextensive with the space intermediate the inner-most end of said anodeand said shield member and subjected to concentrated electric chargingduring normal operation of said device, and an annularly continuous leaddeposition on and confined to only said annular intermediate surfacearea of said envelope, said deposition terminating at pointssubstantially longitudinally spaced inwardly from both ends of saidenvelope and said conductive members and leads extending therethrough,and said deposition comprising an extremely thin flashing diminishing inthickness toward the marginal regions thereof and being electricallyinsulated from all elements in said envelope and from all conductiveelements in the walls of said envelope.

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